1. Field of the Invention
This invention relates to a novel propolis extract, in particular, to a propolis extract where the peculiar odor of propolis is reduced.
2. Description of the Prior Art
Propolis is known as a sticky substance which is used to build the beehives: It is said that there are present in intact propolis a variety of trace ingredients in form of a homogenous mixture with resins, beeswax, essential oils and pollens as predominant ingredients. Propolis has been used from ancient times as medicine for folk remedy in different areas in the world because of its potential antimicrobial and lenitive activities. As described in Shinobu Matsuda, "Foods and Food Ingredients Journal of Japan", No.160, pp.64-73 (1994), recently, other ingredients such as flavonoids and phenol carboxylic acids have been isolated and identified one after another. With the advances in identification and clarification of particular ingredients and their biological activities, the usefulness of propolis as life improving means has been highlighted, thus a variety of health-care and supplemental health-care products have appeared in the market.
By the way, intact propolis is not suitable for use in food products because it usually contains large amounts of contaminants and hardly dissolves in water. In commercialized health-care and supplemental health-care products, propolis is added in the form of extracts which are obtained through the step of soaking crushed propolis mass in ethanol, glycerol and/or water. Propolis has a peculiar odor, which is one of the drawbacks to be overcome but however still not overcome in currently available propolis extracts, thus restricting their use to a few types of food products. Although Japanese Patent Kokai Nos. 165,595/89 and 316,968/93 propose several approaches to improve the appearance and smell of propolis extracts using activated charcoals, synthetic porous adsorbents and cation-exchange resins, each of the approaches has been proved unsuccessful in reducing the peculiar odor of propolis.